Prep time: about 20 minutes.
Baking time: about 15 minutes.
Oven temperature: 225°C, centre of the oven.
2-3 plates deep-frozen puff pastry
500 g rhubarb
75-100 ml sugar
1 egg yolk
1 tbs cornstarch
2 egg whites
100 g icing sugar
Let the puff pastry thaw in the refrigerator. Wash the rhubarb and cut into small pieces.
Put the rhubarb into a round cake pan or pie dish and sprinkle with sugar. Put the dish in an oven and turn the oven up to 225°C and let the dish stand in the oven until the oven has reached full heat, or until the rhubarb is soft. Drain the rhubarb, KEEPING THE LIQUID. Wash the dish. Keep the oven hot.
Arrange the cold puff pastry pieces in a roughly round shape, overlapping them slightly. Reserve a strip of pastry to line the sides of the pie. Roll out into a round shape, about the size of the pie dish/cake pan, and line the bottom of the pan with it. Line the sides of the pan with the remaining pastry.
To make the meringue, whip the egg whites until stiff and whip in the icing sugar. Brush some egg yolk onto the pastry. Put the rhubarb into the dish. Stir the corn-flour into the rhubarb juice and drizzle over the rhubarb. Smooth the meringue over the top of the rhubarb, but not completely to the edges (allow about 5 cm of rhubarb to show along the edge). Bake as indicated above.
Serve warm with whipped cream.